The control of bleeding during surgery accounts for a major portion of the total time involved in an operation. The bleeding that occurs when tissue is incised obscures the surgeon""s vision, reduces his precision and often dictates slow and elaborate procedures in surgical operations. Each bleeding vessel must be grasped in pincer-like clamps to stop the flow of blood and the tissue and vessel within each clamp must then be tied with pieces of fine thread. These ligated masses of tissue die and decompose and thus tend to retard healing and promote infection.
Accordingly, the present invention provides a surgical cutting instrument having a cutting edge which is electrically heated to a constant high temperature for sterilizing the blade, cutting the tissue and cauterizing the surfaces of the incision, thereby allowing surgery to be more rapidly performed. This is accomplished in accordance with the illustrated embodiment of this invention by providing an electrically heated element disposed as the cutting edges of he blade and by providing a control system witch maintains the cutting edge at a high substantially constant temperature during its use. The hot cutting edge according to the present invention decreases the amount of tissue that is damaged and reduces the tendency of the instrument to stick to the heated tissue in the incision. The material used in the electrically heated cutting edge has a negative temperature coefficient of resistance to insure that electrical power applied to the cutting edge is dissipated primarily in the regions thereof which tend to be cooled by contact with tissue. The temperature at which the cutting edge of the blade is maintained depends upon such factors as the nature of the tissue to be cut, the speed of cutting desired, the degree of tissue coagulation desired, and the non-adherence of the blade to the incised tissue and generally is maintained between 300xc2x0-1000xc2x0 Centigrade for typical incisions. The instantaneous temperature of the cutting edge is monitored by measuring the resistance of the heating element itself or through the use of thermocouple elements disposed in the blade near the cutting edge, and the monitoring signal thus derived controls the power applied to the heating element. The handle of the cutting instrument is thermally insulated from the blade to permit comfortable use of the instrument and the handle and blade with its electrically heated cutting edge are detachable for easy replacement and interchangeability with blade, scoops and cutting edge of various shapes and sizes determined by the nature of the incision to be made and the tissue to be cut.